// Given two edges a0a1 and b0b1, check that the minimum distance between them
// is "distance_radians", and that GetEdgePairClosestPoints() returns
// "expected_a" and "expected_b" as the points that achieve this distance.
// S2Point.Empty may be passed for "expected_a" or "expected_b" to indicate
// that both endpoints of the corresponding edge are equally distant, and
// therefore either one might be returned.
//
// Parameters are passed by value so that this function can normalize them.
private static void CheckEdgePairMinDistance(S2Point a0, S2Point a1, S2Point b0, S2Point b1, double distance_radians, S2Point expected_a, S2Point expected_b)
{
a0 = a0.Normalize();
a1 = a1.Normalize();
b0 = b0.Normalize();
b1 = b1.Normalize();
expected_a = expected_a.Normalize();
expected_b = expected_b.Normalize();
var closest = S2.GetEdgePairClosestPoints(a0, a1, b0, b1);
S2Point actual_a = closest.Item1;
S2Point actual_b = closest.Item2;
if (expected_a == S2Point.Empty)
{
// This special value says that the result should be a0 or a1.
Assert.True(actual_a == a0 || actual_a == a1);
}
else
{
Assert.True(S2.ApproxEquals(expected_a, actual_a));
}
if (expected_b == S2Point.Empty)
{
// This special value says that the result should be b0 or b1.
Assert.True(actual_b == b0 || actual_b == b1);
}
else
{
Assert.True(S2.ApproxEquals(expected_b, actual_b));
}
S1ChordAngle min_distance = S1ChordAngle.Zero;
Assert.False(S2.UpdateEdgePairMinDistance(a0, a1, b0, b1, ref min_distance));
min_distance = S1ChordAngle.Infinity;
Assert.True(S2.UpdateEdgePairMinDistance(a0, a1, b0, b1, ref min_distance));
Assert2.Near(distance_radians, min_distance.Radians(), S2.DoubleError);
}
